The average price of a gallon of regular gasoline nationwide went down significantly again in the past week. Gas went down from $2.43 per gallon to $2.36, while it was at $3.42 per gallon one year ago.  There was a significant decrease in Illinois for the past week, as it went down from $2.67 per gallon of regular gas to $2.54.  It decreased significantly in Nashville as well from $2.38 per gallon to $2.28.